/* -------------------------------------------------------------------------------

This code is based on source provided under the terms of the Id Software 
LIMITED USE SOFTWARE LICENSE AGREEMENT, a copy of which is included with the
GtkRadiant sources (see LICENSE_ID). If you did not receive a copy of 
LICENSE_ID, please contact Id Software immediately at info@idsoftware.com.

All changes and additions to the original source which have been developed by
other contributors (see CONTRIBUTORS) are provided under the terms of the
license the contributors choose (see LICENSE), to the extent permitted by the
LICENSE_ID. If you did not receive a copy of the contributor license,
please contact the GtkRadiant maintainers at info@gtkradiant.com immediately.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS IS''
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY
DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

----------------------------------------------------------------------------------

This code has been altered significantly from its original form, to support
several games based on the Quake III Arena engine, in the form of "Q3Map2."

------------------------------------------------------------------------------- */



/* marker */
#define PATCH_C



/* dependencies */
#include "q3map2.h"



/*
ExpandLongestCurve() - ydnar
finds length of quadratic curve specified and determines if length is longer than the supplied max
*/

#define APPROX_SUBDIVISION	8

static void ExpandLongestCurve( float *longestCurve, vec3_t a, vec3_t b, vec3_t c )
{
	int		i;
	float	t, len;
	vec3_t	ab, bc, ac, pt, last, delta;
	
	
	/* calc vectors */
	VectorSubtract( b, a, ab );
	if( VectorNormalize( ab, ab ) < 0.125f )
		return;
	VectorSubtract( c, b, bc );
	if( VectorNormalize( bc, bc ) < 0.125f )
		return;
	VectorSubtract( c, a, ac );
	if( VectorNormalize( ac, ac ) < 0.125f )
		return;
	
	/* if all 3 vectors are the same direction, then this edge is linear, so we ignore it */
	if( DotProduct( ab, bc ) > 0.99f && DotProduct( ab, ac ) > 0.99f )
		return;
	
	/* recalculate vectors */
	VectorSubtract( b, a, ab );
	VectorSubtract( c, b, bc );
	
	/* determine length */
	VectorCopy( a, last );
	for( i = 0, len = 0.0f, t = 0.0f; i < APPROX_SUBDIVISION; i++, t += (1.0f / APPROX_SUBDIVISION) )
	{
		/* calculate delta */
		delta[ 0 ] = ((1.0f - t) * ab[ 0 ]) + (t * bc[ 0 ]);
		delta[ 1 ] = ((1.0f - t) * ab[ 1 ]) + (t * bc[ 1 ]);
		delta[ 2 ] = ((1.0f - t) * ab[ 2 ]) + (t * bc[ 2 ]);
		
		/* add to first point and calculate pt-pt delta */
		VectorAdd( a, delta, pt );
		VectorSubtract( pt, last, delta );
		
		/* add it to length and store last point */
		len += VectorLength( delta );
		VectorCopy( pt, last );
	}
	
	/* longer? */
	if( len > *longestCurve )
		*longestCurve = len;
}



/*
ExpandMaxIterations() - ydnar
determines how many iterations a quadratic curve needs to be subdivided with to fit the specified error
*/

static void ExpandMaxIterations( int *maxIterations, int maxError, vec3_t a, vec3_t b, vec3_t c )
{
	int				i, j;
	vec3_t			prev, next, mid, delta, delta2;
	float			len, len2;
	int				numPoints, iterations;
	vec3_t			points[ MAX_EXPANDED_AXIS ];
	
	
	/* initial setup */
	numPoints = 3;
	VectorCopy( a, points[ 0 ] );
	VectorCopy( b, points[ 1 ] );
	VectorCopy( c, points[ 2 ] );

	/* subdivide */
	for( i = 0; i + 2 < numPoints; i += 2 )
	{
		/* check subdivision limit */
		if( numPoints + 2 >= MAX_EXPANDED_AXIS )
			break;
		
		/* calculate new curve deltas */
		for( j = 0; j < 3; j++ )
		{
			prev[ j ] = points[ i + 1 ][ j ] - points[ i ][ j ]; 
			next[ j ] = points[ i + 2 ][ j ] - points[ i + 1 ][ j ]; 
			mid[ j ] = (points[ i ][ j ] + points[ i + 1 ][ j ] * 2.0f + points[ i + 2 ][ j ]) * 0.25f;
		}
		
		/* see if this midpoint is off far enough to subdivide */
		VectorSubtract( points[ i + 1 ], mid, delta );
		len = VectorLength( delta );
		if( len < maxError )
			continue;
		
		/* subdivide */
		numPoints += 2;
		
		/* create new points */
		for( j = 0; j < 3; j++ )
		{
			prev[ j ] = 0.5f * (points[ i ][ j ] + points[ i + 1 ][ j ]);
			next[ j ] = 0.5f * (points[ i + 1 ][ j ] + points[ i + 2 ][ j ]);
			mid[ j ] = 0.5f * (prev[ j ] + next[ j ]);
		}
		
		/* push points out */
		for( j = numPoints - 1; j > i + 3; j-- )
			VectorCopy( points[ j - 2 ], points[ j ] );
		
		/* insert new points */
		VectorCopy( prev, points[ i + 1 ] );
		VectorCopy( mid, points[ i + 2 ] );
		VectorCopy( next, points[ i + 3 ] );

		/* back up and recheck this set again, it may need more subdivision */
		i -= 2;
	}
	
	/* put the line on the curve */
	for( i = 1; i < numPoints; i += 2 )
	{
		for( j = 0; j < 3; j++ )
		{
			prev[ j ] = 0.5f * (points[ i ][ j ] + points[ i + 1 ][ j ] );
			next[ j ] = 0.5f * (points[ i ][ j ] + points[ i - 1 ][ j ] );
			points[ i ][ j ] = 0.5f * (prev[ j ] + next[ j ]);
		}
	}
	
	/* eliminate linear sections */
	for( i = 0; i + 2 < numPoints; i++ )
	{
		/* create vectors */
		VectorSubtract( points[ i + 1 ], points[ i ], delta );
		len = VectorNormalize( delta, delta );
		VectorSubtract( points[ i + 2 ], points[ i + 1 ], delta2 );
		len2 = VectorNormalize( delta2, delta2 );
		
		/* if either edge is degenerate, then eliminate it */
		if( len < 0.0625f || len2 < 0.0625f || DotProduct( delta, delta2 ) >= 1.0f )
		{
			for( j = i + 1; j + 1 < numPoints; j++ )
				VectorCopy( points[ j + 1 ], points[ j ] );
			numPoints--;
			continue;
		}
	}
	
	/* the number of iterations is 2^(points - 1) - 1 */
	numPoints >>= 1;
	iterations = 0;
	while( numPoints > 1 )
	{
		numPoints >>= 1;
		iterations++;
	}
	
	/* more? */
	if( iterations > *maxIterations )
		*maxIterations = iterations;
}



/*
ParsePatch()
creates a mapDrawSurface_t from the patch text
*/

void ParsePatch( qboolean onlyLights )
{
	vec_t			info[ 5 ];
	int				i, j, k;
	parseMesh_t		*pm;
	char			texture[ MAX_QPATH ];
	char			shader[ MAX_QPATH ];
	mesh_t			m;
	bspDrawVert_t	*verts;
	epair_t			*ep;
	vec4_t			delta, delta2, delta3;
	qboolean		degenerate;
	float			longestCurve;
	int				maxIterations;
	
	
	MatchToken( "{" );
	
	/* get texture */
	GetToken( qtrue );
	strcpy( texture, token );
	
	Parse1DMatrix( 5, info );
	m.width = info[0];
	m.height = info[1];
	m.verts = verts = safe_malloc( m.width * m.height * sizeof( m.verts[0] ) );
	
	if( m.width < 0 || m.width > MAX_PATCH_SIZE || m.height < 0 || m.height > MAX_PATCH_SIZE )
		Error( "ParsePatch: bad size" );
	
	MatchToken( "(" );
	for( j = 0; j < m.width ; j++ )
	{
		MatchToken( "(" );
		for( i = 0; i < m.height ; i++ )
		{
			Parse1DMatrix( 5, verts[ i * m.width + j ].xyz );
			
			/* ydnar: fix colors */
			for( k = 0; k < MAX_LIGHTMAPS; k++ )
			{
				verts[ i * m.width + j ].color[ k ][ 0 ] = 255;
				verts[ i * m.width + j ].color[ k ][ 1 ] = 255;
				verts[ i * m.width + j ].color[ k ][ 2 ] = 255;
				verts[ i * m.width + j ].color[ k ][ 3 ] = 255;
			}
		}
		MatchToken( ")" );
	}
	MatchToken( ")" );

	// if brush primitives format, we may have some epairs to ignore here
	GetToken(qtrue);
	if (g_bBrushPrimit!=BPRIMIT_OLDBRUSHES && strcmp(token,"}"))
	{
		// NOTE: we leak that!
		ep = ParseEPair();
	}
	else
		UnGetToken();

	MatchToken( "}" );
	MatchToken( "}" );
	
	/* short circuit */
	if( noCurveBrushes || onlyLights )
		return;
	
	
	/* ydnar: delete and warn about degenerate patches */
	j = (m.width * m.height);
	VectorClear( delta );
	delta[ 3 ] = 0;
	degenerate = qtrue;
	
	/* find first valid vector */
	for( i = 1; i < j && delta[ 3 ] == 0; i++ )
	{
		VectorSubtract( m.verts[ 0 ].xyz, m.verts[ i ].xyz, delta );
		delta[ 3 ] = VectorNormalize( delta, delta );
	}
	
	/* secondary degenerate test */
	if( delta[ 3 ] == 0 )
		degenerate = qtrue;
	else
	{
		/* if all vectors match this or are zero, then this is a degenerate patch */
		for( i = 1; i < j && degenerate == qtrue; i++ )
		{
			VectorSubtract( m.verts[ 0 ].xyz, m.verts[ i ].xyz, delta2 );
			delta2[ 3 ] = VectorNormalize( delta2, delta2 );
			if( delta2[ 3 ] != 0 )
			{
				/* create inverse vector */
				VectorCopy( delta2, delta3 );
				delta3[ 3 ] = delta2[ 3 ];
				VectorInverse( delta3 );
				
				/* compare */
				if( VectorCompare( delta, delta2 ) == qfalse && VectorCompare( delta, delta3 ) == qfalse )
					degenerate = qfalse;
			}
		}
	}
	
	/* warn and select degenerate patch */
	if( degenerate )
	{
		xml_Select( "degenerate patch", mapEnt->mapEntityNum, entitySourceBrushes, qfalse );
		free( m.verts );
		return;
	}
	
	/* find longest curve on the mesh */
	longestCurve = 0.0f;
	maxIterations = 0;
	for( j = 0; j + 2 < m.width; j += 2 )
	{
		for( i = 0; i + 2 < m.height; i += 2 )
		{
			ExpandLongestCurve( &longestCurve, verts[ i * m.width + j ].xyz, verts[ i * m.width + (j + 1) ].xyz, verts[ i * m.width + (j + 2) ].xyz );		/* row */
			ExpandLongestCurve( &longestCurve, verts[ i * m.width + j ].xyz, verts[ (i + 1) * m.width + j ].xyz, verts[ (i + 2) * m.width + j ].xyz );		/* col */
			ExpandMaxIterations( &maxIterations, patchSubdivisions, verts[ i * m.width + j ].xyz, verts[ i * m.width + (j + 1) ].xyz, verts[ i * m.width + (j + 2) ].xyz );		/* row */
			ExpandMaxIterations( &maxIterations, patchSubdivisions, verts[ i * m.width + j ].xyz, verts[ (i + 1) * m.width + j ].xyz, verts[ (i + 2) * m.width + j ].xyz  );	/* col */
		}
	}
	
	/* allocate patch mesh */
	pm = safe_malloc( sizeof( *pm ) );
	memset( pm, 0, sizeof( *pm ) );
	
	/* ydnar: add entity/brush numbering */
	pm->entityNum = mapEnt->mapEntityNum;
	pm->brushNum = entitySourceBrushes;
	
	/* set shader */
	sprintf( shader, "textures/%s", texture );
	pm->shaderInfo = ShaderInfoForShader( shader );
	
	/* set mesh */
	pm->mesh = m;
	
	/* set longest curve */
	pm->longestCurve = longestCurve;
	pm->maxIterations = maxIterations;
	
	/* link to the entity */
	pm->next = mapEnt->patches;
	mapEnt->patches = pm;
}



/*
GrowGroup_r()
recursively adds patches to a lod group
*/

static void GrowGroup_r( parseMesh_t *pm, int patchNum, int patchCount, parseMesh_t **meshes, byte *bordering, byte *group )
{
	int			i;
	const byte	*row;
	
	
	/* early out check */
	if( group[ patchNum ] )
		return;
	
	
	/* set it */
	group[ patchNum ] = 1;
	row = bordering + patchNum * patchCount;
	
	/* check maximums */
	if( meshes[ patchNum ]->longestCurve > pm->longestCurve )
		pm->longestCurve = meshes[ patchNum ]->longestCurve;
	if( meshes[ patchNum ]->maxIterations > pm->maxIterations )
		pm->maxIterations = meshes[ patchNum ]->maxIterations;
	
	/* walk other patches */
	for( i = 0; i < patchCount; i++ )
	{
		if( row[ i ] )
			GrowGroup_r( pm, i, patchCount, meshes, bordering, group );
	}
}


/*
PatchMapDrawSurfs()
any patches that share an edge need to choose their
level of detail as a unit, otherwise the edges would
pull apart.
*/

void PatchMapDrawSurfs( entity_t *e )
{
	int						i, j, k, l, c1, c2;
	parseMesh_t				*pm;
	parseMesh_t				*check, *scan;
	mapDrawSurface_t		*ds;
	int						patchCount, groupCount;
	bspDrawVert_t			*v1, *v2;
	vec3_t					bounds[ 2 ];
	byte					*bordering;
	
	/* ydnar: mac os x fails with these if not static */
	MAC_STATIC parseMesh_t	*meshes[ MAX_MAP_DRAW_SURFS ];
	MAC_STATIC qb_t			grouped[ MAX_MAP_DRAW_SURFS ];
	MAC_STATIC byte			group[ MAX_MAP_DRAW_SURFS ];
	
	
	/* note it */
	Sys_FPrintf( SYS_VRB, "--- PatchMapDrawSurfs ---\n" );

	patchCount = 0;
	for ( pm = e->patches ; pm ; pm = pm->next  ) {
		meshes[patchCount] = pm;
		patchCount++;
	}

	if ( !patchCount ) {
		return;
	}
	bordering = safe_malloc( patchCount * patchCount );
	memset( bordering, 0, patchCount * patchCount );

	// build the bordering matrix
	for ( k = 0 ; k < patchCount ; k++ ) {
		bordering[k*patchCount+k] = 1;

		for ( l = k+1 ; l < patchCount ; l++ ) {
			check = meshes[k];
			scan = meshes[l];
			c1 = scan->mesh.width * scan->mesh.height;
			v1 = scan->mesh.verts;

			for ( i = 0 ; i < c1 ; i++, v1++ ) {
				c2 = check->mesh.width * check->mesh.height;
				v2 = check->mesh.verts;
				for ( j = 0 ; j < c2 ; j++, v2++ ) {
					if ( fabs( v1->xyz[0] - v2->xyz[0] ) < 1.0
						&& fabs( v1->xyz[1] - v2->xyz[1] ) < 1.0
						&& fabs( v1->xyz[2] - v2->xyz[2] ) < 1.0 ) {
						break;
					}
				}
				if ( j != c2 ) {
					break;
				}
			}
			if ( i != c1 ) {
				// we have a connection
				bordering[k*patchCount+l] =
				bordering[l*patchCount+k] = 1;
			} else {
				// no connection
				bordering[k*patchCount+l] =
				bordering[l*patchCount+k] = 0;
			}

		}
	}

	/* build groups */
	memset( grouped, 0, patchCount );
	groupCount = 0;
	for ( i = 0; i < patchCount; i++ )
	{
		/* get patch */
		scan = meshes[ i ];
		
		/* start a new group */
		if( !grouped[ i ] )
			groupCount++;
		
		/* recursively find all patches that belong in the same group */
		memset( group, 0, patchCount );
		GrowGroup_r( scan, i, patchCount, meshes, bordering, group );
		
		/* bound them */
		ClearBounds( bounds[ 0 ], bounds[ 1 ] );
		for( j = 0; j < patchCount; j++ )
		{
			if ( group[ j ] )
			{
				grouped[ j ] = qtrue;
				check = meshes[ j ];
				c1 = check->mesh.width * check->mesh.height;
				v1 = check->mesh.verts;
				for( k = 0; k < c1; k++, v1++ )
					AddPointToBounds( v1->xyz, bounds[ 0 ], bounds[ 1 ] );
			}
		}
		
		/* debug code */
		//%	Sys_Printf( "Longest curve: %f Iterations: %d\n", scan->longestCurve, scan->maxIterations );
		
		/* create drawsurf */
		scan->grouped = qtrue;
		ds = DrawSurfaceForMesh( e, scan, NULL );	/* ydnar */
		VectorCopy( bounds[ 0 ], ds->bounds[ 0 ] );
		VectorCopy( bounds[ 1 ], ds->bounds[ 1 ] );
	}
	
	/* emit some statistics */
	Sys_FPrintf( SYS_VRB, "%9d patches\n", patchCount );
	Sys_FPrintf( SYS_VRB, "%9d patch LOD groups\n", groupCount );
}

